iio: accel: add support for the Domintech DMARD09 3-axis accelerometer
Minimal implementation of an IIO driver for the Domintech DMARD09 3-axis
accelerometer. Only supports reading the x,y,z axes at the moment.
Implementation based on the Android driver from the Acer Liquid E2
kernel sources.
Signed-off-by: Jelle van der Waa <jelle@vdwaa.nl>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/accel/dmard09.c b/drivers/iio/accel/dmard09.c
new file mode 100644
index 0000000..d3a28f9
--- /dev/null
+++ b/drivers/iio/accel/dmard09.c
@@ -0,0 +1,157 @@
+/*
+ * IIO driver for the 3-axis accelerometer Domintech DMARD09.
+ *
+ * Copyright (c) 2016, Jelle van der Waa <jelle@vdwaa.nl>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <asm/unaligned.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+
+#define DMARD09_DRV_NAME "dmard09"
+
+#define DMARD09_REG_CHIPID 0x18
+#define DMARD09_REG_STAT 0x0A
+#define DMARD09_REG_X 0x0C
+#define DMARD09_REG_Y 0x0E
+#define DMARD09_REG_Z 0x10
+#define DMARD09_CHIPID 0x95
+
+#define DMARD09_BUF_LEN 8
+#define DMARD09_AXIS_X 0
+#define DMARD09_AXIS_Y 1
+#define DMARD09_AXIS_Z 2
+#define DMARD09_AXIS_X_OFFSET ((DMARD09_AXIS_X + 1) * 2)
+#define DMARD09_AXIS_Y_OFFSET ((DMARD09_AXIS_Y + 1 )* 2)
+#define DMARD09_AXIS_Z_OFFSET ((DMARD09_AXIS_Z + 1) * 2)
+
+struct dmard09_data {
+ struct i2c_client *client;
+};
+
+#define DMARD09_CHANNEL(_axis, offset) { \
+ .type = IIO_ACCEL, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .modified = 1, \
+ .address = offset, \
+ .channel2 = IIO_MOD_##_axis, \
+}
+
+static const struct iio_chan_spec dmard09_channels[] = {
+ DMARD09_CHANNEL(X, DMARD09_AXIS_X_OFFSET),
+ DMARD09_CHANNEL(Y, DMARD09_AXIS_Y_OFFSET),
+ DMARD09_CHANNEL(Z, DMARD09_AXIS_Z_OFFSET),
+};
+
+static int dmard09_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct dmard09_data *data = iio_priv(indio_dev);
+ u8 buf[DMARD09_BUF_LEN];
+ int ret;
+ s16 accel;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ /*
+ * Read from the DMAR09_REG_STAT register, since the chip
+ * caches reads from the individual X, Y, Z registers.
+ */
+ ret = i2c_smbus_read_i2c_block_data(data->client,
+ DMARD09_REG_STAT,
+ DMARD09_BUF_LEN, buf);
+ if (ret < 0) {
+ dev_err(&data->client->dev, "Error reading reg %d\n",
+ DMARD09_REG_STAT);
+ return ret;
+ }
+
+ accel = get_unaligned_le16(&buf[chan->address]);
+
+ /* Remove lower 3 bits and sign extend */
+ accel <<= 4;
+ accel >>= 7;
+
+ *val = accel;
+
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info dmard09_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = dmard09_read_raw,
+};
+
+static int dmard09_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int ret;
+ struct iio_dev *indio_dev;
+ struct dmard09_data *data;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev) {
+ dev_err(&client->dev, "iio allocation failed\n");
+ return -ENOMEM;
+ }
+
+ data = iio_priv(indio_dev);
+ data->client = client;
+
+ ret = i2c_smbus_read_byte_data(data->client, DMARD09_REG_CHIPID);
+ if (ret < 0) {
+ dev_err(&client->dev, "Error reading chip id %d\n", ret);
+ return ret;
+ }
+
+ if (ret != DMARD09_CHIPID) {
+ dev_err(&client->dev, "Invalid chip id %d\n", ret);
+ return -ENODEV;
+ }
+
+ i2c_set_clientdata(client, indio_dev);
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->name = DMARD09_DRV_NAME;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = dmard09_channels;
+ indio_dev->num_channels = ARRAY_SIZE(dmard09_channels);
+ indio_dev->info = &dmard09_info;
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id dmard09_id[] = {
+ { "dmard09", 0},
+ { },
+};
+
+MODULE_DEVICE_TABLE(i2c, dmard09_id);
+
+static struct i2c_driver dmard09_driver = {
+ .driver = {
+ .name = DMARD09_DRV_NAME
+ },
+ .probe = dmard09_probe,
+ .id_table = dmard09_id,
+};
+
+module_i2c_driver(dmard09_driver);
+
+MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>");
+MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver");
+MODULE_LICENSE("GPL");